Performances
============

Transaction performances are evaluated based on response time (Time to Last Byte or TTLB), which is converted into a score from 0 to 100
(higher is better). We call this rating TPDEX (Transaction Performance Index).

This score is then converted into a letter rating for display.

.. figure:: images/tpdex.png
   :align: center
   :alt: Transaction Performance Index

   Response time (TTLB) to Transaction Performance Index (TPDEX)

* **Y Axis**: TPDEX
* **X Axis**: TTLB in milliseconds

Letter Rating
:::::::::::::

+----------------------+-------------------------+---------------------+
| TPDEX threshold      | Response time threshold | Rating              |
+======================+=========================+=====================+
| 98                   | 25ms                    | A++                 |
+----------------------+-------------------------+---------------------+
| 96                   | 50ms                    | A+                  |
+----------------------+-------------------------+---------------------+
| 93                   | 100ms                   | A                   |
+----------------------+-------------------------+---------------------+
| 83                   | 250ms                   | B                   |
+----------------------+-------------------------+---------------------+
| 69                   | 500ms                   | C                   |
+----------------------+-------------------------+---------------------+
| 49                   | 1s                      | D                   |
+----------------------+-------------------------+---------------------+
| 31                   | 2s                      | E                   |
+----------------------+-------------------------+---------------------+
| 17                   | 4s                      | F                   |
+----------------------+-------------------------+---------------------+
| 0                    | ∞                       | G                   |
+----------------------+-+-----------------------+---------------------+